Science hasnt conclusively ruled out the existence of ghosts and vampires, but two physicists have now proved that certain behavior often attributed to them is impossible.
In their paper Ghosts, Vampires and Zombies: Cinema Fiction vs. Physics Reality, University of Central Florida theoretical physics professor Costas Efthimiou and graduate student Sohang Gandhi explore inconsistencies in undead conduct as portrayed in popular films and folklore, and take issue with movies like Blade, The Sixth Sense and Ghost.
Take Blade. In New Line Cinemas 1998 vampire flick, the fanged night-dwellers feed on the blood of humans, who, once bitten, turn into vampires themselves. Impossible, says Efthimiou–and he uses a basic math principle, geometric progression, to prove it.
He begins with the assumption that a vampire feeds only once a month. Certainly a highly conservative assumption, the paper notes. Every time the vampire feeds, the vampire population increases by one and the human population decreases by one. Efthimiou supposed that the first vampire arrived on Jan. 1, 1600, when the human population was 536,870,911. That means there would have been two vampires and 536,870,910 humans on Feb. 1, four vampires and 536,870,908 humans on March 1, and so forth. With the vampire population increasing geometrically and the human population decreasing geometrically, by the 30th month the human race would have been wiped out.
In the long run, humans cannot survive under these conditions, even if our population were doubling each month, Efthimiou says, and doubling is clearly way beyond the human capacity of reproduction. Zombies, also thought to turn victims into their own kind, present a similar problem.
Ghosts that can walk through walls, meanwhile, are scientific oxymorons. For ghosts to be able to walk like humans–picture Patrick Swayzes ethereal presence in Paramounts Ghost–they would have to put force upon the floor, which in return would exert an equal and opposite force. Walking, in short, depends on Newtons third law of physics, which states that for each action there is an equal but opposite reaction.
However, ghosts uncanny ability to pass through walls and even through living humans demonstrates that they cannot apply any force at all. Put a different way, movies posit that ghosts are both material and material-less. But even if they exhibited selective material-lessness, Efthimiou notes, we humans should be able to place stress sensors on the floor to detect the ghosts presence.
Now if only some scientists would skewer the improbabilities of romantic comedies and action thrillers.
In the Papers takes a weekly look at a new study or research paper in the sciences or social sciences.